I’ve been performing the recommended maintenance, and from the front everything looked fine:
However, a look from underneath the printhead revealed a horror show:
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It does look like a horror show, mate.
It looks like there’s a chance it could set itself on fire.
I would let Bambu know to see how dangerous it could be.
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it looks pretty gnarly but if you put the sock on, heat that nozzle to operating temp for 2-3 mins, take the sock off, put your glove on, and wipe it down itll be gone in an instant. The A1 nozzles get similar.
I dont think its a fire risk - you can look up combustion temp of all the material you plan on putting thru the hotend - but its certainly not ideal
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I don’t see a fire risk either, as nothing will ever get hotter than the hotend. The bigger issue is how to clean all that gunk off the wiring, which looks to be rather fragile. I can’t just heat up the gunk and try to pull it off without risking breaking the wire. Maybe I just need to order replacements and go with “all new” again, or at least have it already on hand as a backup in case I do end up breaking it during the cleanup.
By the way, something I learned just now is that the sensor in the photo is an Eddy Sensor, aka the Nozzle Wrap Detection Sensor, whose job is to detect if molten filament has wrapped around or oozed onto the nozzle — a common issue that can cause stringing, blobs, or clogs. I had previously thought that was checked for optically using the camera, but no, this does the business. The other nozzle also has one. This eddy sensor is different from the one used to calibrate nozzle height, which is located in the back:
I’m surprised Bambulab doesn’t advertise the existence of the Nozzle Wrap Detection Sensor, because it’s a highly important and valuable feature (well, at least to me) that I’m not aware of any other printers having:
From the looks of it, it might only be the right hand heating assembly that needs replacement (before it becomes too gunked up to make even that difficult):
I have probably close to 2000 hours on this printer, so if that gets me back to “good as new”, I’m OK with that. Hopefully it’s not a difficult swap.
I have to give some credit to Bambulab technical support here. I opened a ticket and uploaded the same photo to them, and they replied within 9 hours with some suggestions. Their suggestions was:
You can refer to the following link for instructions on cleaning the nozzle and surrounding parts：
H2D Nozzle/Hotend Unclogging Procedure | Bambu Lab Wiki
H2D Nozzle Cold Pull Maintenance and Cleaning | Bambu Lab Wiki
So, even though these suggestions seemed to miss the point entirely, I at least commend them on the rapid turnaround, 
though quite honestly it’s not useful at all, since it’s in reference to internal nozzle clogs, not the open region behind the nozzle. Well, what can I say? Maybe: A picture is worth a thousand words, none of which translate? Or maybe there simply is no such thing as self-evident? Maybe their first response is AI generated. I wouldn’t be surprised. Just not a very good AI. In any case, I provided them with feedback, and we’ll see whether it gets any better or becomes just another response based solely on a keyword match. My guess is that to get a response from a real human will take longer, probably much longer.
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The response you received really doesn’t even come close to addressing your problem. The support team sometimes gives completely irrelevant answers to the issues we report, almost as if they’re mocking us. I can’t believe they would respond to your problem, which you explained with videos and pictures, with something like “how to clean a nozzle.” As you said, if an AI is answering this, then we’ll have a really hard time when we actually encounter a problem.
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I had this happen to mine because of an incorrectly installed waste chute. Bambu supplied a new heater assembly under warranty
@GeoffS Can you say anything more. e.g. how would I know whether mine was also incorrectly installed? Except on one occasion, I haven’t noticed the waste chute clog up. Was that the primary symptom, or was it something else?
Have a look at this thread
I posted an update to this topic here: